Friction roller type continuously variable transmission

Abstract

Herein disclosed is a friction roller type continuously variable transmission which is compact in size. The transmission comprises a casing, input and output cone discs facing each other, two friction rollers each being operatively disposed between the input and output cone discs, two roller supporting members for rotatably supporting the friction rollers, first and second bearing supporting members each having opposed ends which are connected to one ends of the roller supporting members through respective bearings, first and second link posts supporting middle portions of the first and second bearing supporting members respectively, and a control valve body installing therein various control valves for controlling operation of the transmission, the control valve body being secured to the casing. In order to reduce the size of the entire construction of the transmission, the first link post is fixed to the casing, while the second link post is fixed to the control valve body.

What is claimed is: 
     
       1. A friction roller type continuously variable transmission comprising: a casing;   input and output discs facing each other;   a pair of friction rollers each having diametrically opposed sides frictionally engaged with said input and output discs respectively;   two roller supporting members for rotatably supporting said friction rollers respectively;   a first bearing supporting member having opposed ends which are connected to one ends of said roller supporting members through respective bearings;   a second bearing supporting member having opposed ends which are connected to the other ends of said roller supporting member through respective bearings;   a first link post for supporting a middle portion of said first bearing supporting member;   a second link post for supporting a middle portion of said second bearing supporting member;   a control valve body installing therein various control valves for controlling operation of the transmission, said control valve body being secured to said casing;   said first link post being fixed to said casing, said second link post being fixed to said control valve body;   a plurality of piston devices installed in said control valve body, said piston devices moving said roller supporting members when actuated;   each of said piston devices comprising:   a piston sealingly and slidably disposed in a cylinder formed in said control valve body in a manner to define in the cylinder two operation chambers bounded by said piston;   a shaft slidably passing through a hollow formed in said piston and having one end connected to one of said roller supporting members; and   wherein said piston has at least a portion which is projected outwardly from said control valve body to abut on said roller supporting member.   
     
     
       2. A friction roller type continuously variable transmission as claimed in claim 1 further comprising a link mechanism which comprises: a cam secured to said shaft to move therewith;   a bell-crank lever pivotally connected to said valve control body, said lever having one end operatively engaged with said cam and the other end operatively connected to a part of a speed control valve arranged in said control valve body.   
     
     
       3. A friction roller type continuously variable transmission as claimed in claim 2 in which said speed control valve comprises: a driving rod rotated by a motor;   a sleeve coaxially disposed in a bore formed in said control valve body, said sleeve being connected to said driving rod in such a manner that rotation of said driving rod about its axis being about an axial movement of said sleeve in said bores;   a spool axially slidably disposed in said sleeve, one end of said speed being in engagement with the other end of said bell-crank lever; and   a spring disposed in said sleeve to bias said spool toward said bell-crank lever.   
     
     
       4. A friction roller type continuously variable transmission as claimed in claim 3, in which said spool has axially spaced two lands which can close fluid passages which lead to said operation chambers of said cylinder respectively. 
     
     
       5. A friction roller type continuously variable transmission comprising: a casing;   input and output discs facing each other;   a pair of friction rollers each having diametrically opposed sides frictionally engaged with said input and output discs respectively;   two roller supporting members for rotatably supporting said friction rollers respectively;   a first bearing supporting member having opposed ends which are connected to one ends of said roller supporting members through respective bearings;   a second bearing supporting member having opposed ends which are connected to the other ends of said roller supporting member through respective bearings;   a first link post for supporting a middle portion of said first bearing supporting member;   a second link post for supporting a middle portion of said second bearing supporting member;   a control valve body installing therein various control valves for controlling operation of the transmission, said control valve body being secured to said casing;   said first link post being fixed to said casing, said second link post being fixed to said control valve body;   a plurality of piston devices installed in said control valve body, said piston devices moving said roller supporting members when actuated;   each of said piston devices comprising:   a piston having a hollow stem portion and sealingly and slidably disposed in a cylinder formed in said control valve body;   a bolt passing through said hollow stem portion of the piston and secured at its one end to one of said roller supporting members;   a sleeve coaxially disposed between said bolt and said hollow stem portion of the piston; and   wherein one end of said stem portion is projected outwardly from said control valve body and is spaced from said roller supporting member through a biasing means which abuts said stem portion and said roller supporting member.   
     
     
       6. A friction roller type continuously variable transmission as claimed in claim 5 wherein said biasing means is dish spring which is compressed between siad one end of the stem portion and said roller supporting member.